The present invention relates to an optical pickup device and an optical disc apparatus.
As a background art in this technical field, there is, for example, JP-A-2006-344344. This publication describes that “a desired signal is acquired at high precision from an optical disc having a plurality of recording layers”. There is also, for example, JP-A-2006-344380. This publication describes that “even if a writable optical storage medium having two information recording planes is used, a tracking signal having a small offset is detected” Further, for example, Technical Report of IEICE, CPM2005-149 (2005-10, p. 33, FIGS. 4 and 5) describes that “a tracking photodetector is disposed in an area where there is no stray light.